﻿using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

/// <summary>
/// The SqlHelper class is intended to encapsulate high performance, 
/// scalable best practices for common uses of SqlClient.
/// </summary>
public sealed class SqlHelper
{
    private SqlHelper() { }

    //Database connection strings
    //public static readonly string CONN_STRING = ConfigurationManager.ConnectionStrings["connectionStr"].ConnectionString;

    /// <summary>
    /// Execute a SqlCommand that returns a resultset against the database specified in the connection string 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.:  
    ///  SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="cmdType">the CommandType (stored procedure, text, etc.)</param>
    /// <param name="cmdText">the stored procedure name or T-SQL command</param>
    /// <param name="cmdParms">an array of SqlParamters used to execute the command</param>
    /// <returns>A SqlDataReader containing the results</returns>
    public static SqlDataReader ExecuteReader(CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
    {
        SqlCommand cmd = new SqlCommand();
        //SqlConnection conn = new SqlConnection(CONN_STRING);

        // we use a try/catch here because if the method throws an exception we want to 
        // close the connection throw code, because no datareader will exist, hence the 
        // commandBehaviour.CloseConnection will not work
        try
        {
            PrepareCommand(cmd, Connection, null, cmdType, cmdText, cmdParms);
            SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            cmd.Parameters.Clear();
            return rdr;
        }
        catch
        {
            //conn.Close();
            throw;
        }
    }
    public static SqlDataReader ExecuteReader(string cmdText, params SqlParameter[] cmdParms)
    {
        return ExecuteReader(CommandType.Text, cmdText, cmdParms);
    }

    /// <summary>
    /// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.:  
    ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="cmdType">the CommandType (stored procedure, text, etc.)</param>
    /// <param name="cmdText">the stored procedure name or T-SQL command</param>
    /// <param name="cmdParms">an array of SqlParamters used to execute the command</param>
    /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
    public static object ExecuteScalar(CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
    {
        SqlCommand cmd = new SqlCommand();

        PrepareCommand(cmd, Connection, null, cmdType, cmdText, cmdParms);
        object val = cmd.ExecuteScalar();
        cmd.Parameters.Clear();
        return val;
    }
    public static object ExecuteScalar(string cmdText, params SqlParameter[] cmdParms)
    {
        return ExecuteScalar(CommandType.Text, cmdText, cmdParms);
    }

    /// <summary>
    /// Execute a SqlCommand that returns the first column of the first record against an existing database connection 
    /// using the provided parameters.
    /// </summary>
    /// <remarks>
    /// e.g.:  
    ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="conn">an existing database connection</param>
    /// <param name="cmdType">the CommandType (stored procedure, text, etc.)</param>
    /// <param name="cmdText">the stored procedure name or T-SQL command</param>
    /// <param name="cmdParms">an array of SqlParamters used to execute the command</param>
    /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
    public static object ExecuteScalar(SqlConnection conn, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
    {

        SqlCommand cmd = new SqlCommand();

        PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
        object val = cmd.ExecuteScalar();
        cmd.Parameters.Clear();
        return val;
    }


    /// <summary>
    /// Prepare a command for execution
    /// </summary>
    /// <param name="cmd">SqlCommand object</param>
    /// <param name="conn">SqlConnection object</param>
    /// <param name="trans">SqlTransaction object</param>
    /// <param name="cmdType">Cmd type e.g. stored procedure or text</param>
    /// <param name="cmdText">Command text, e.g. Select * from Products</param>
    /// <param name="cmdParms">SqlParameters to use in the command</param>
    private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
    {

        //if (conn.State != ConnectionState.Open)
        //    conn.Open();
        cmd.Connection = conn;
        cmd.CommandText = cmdText;

        if (trans != null)
            cmd.Transaction = trans;

        cmd.CommandType = cmdType;

        if (cmdParms != null)
        {
            foreach (SqlParameter parm in cmdParms)
                cmd.Parameters.Add(parm);
        }
    }
    public static void ExecuteNonQuery(CommandType cmdType, string cmdText, params SqlParameter[] cmdParams)
    {
        SqlCommand cmd = new SqlCommand();
        PrepareCommand(cmd, Connection, null, cmdType, cmdText, cmdParams);
        object val = cmd.ExecuteNonQuery();
        cmd.Parameters.Clear();
    }
    public static void ExecuteNonQuery(string cmdText, params SqlParameter[] cmdParams)
    {
        ExecuteNonQuery(CommandType.Text, cmdText, cmdParams);
    }
    public static DataSet ExecuteDataset(CommandType cmdType, string cmdText, params SqlParameter[] cmdParams)
    {
        SqlCommand cmd = new SqlCommand();
        PrepareCommand(cmd, Connection, null, cmdType, cmdText, cmdParams);
        //create the DataAdapter & DataSet
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();

        //fill the DataSet using default values for DataTable names, etc.
        da.Fill(ds);

        // detach the SqlParameters from the command object, so they can be used again.			
        cmd.Parameters.Clear();

        //return the dataset
        return ds;
    }
    public static DataSet ExecuteDataset(string cmdText, params SqlParameter[] cmdParams)
    {
        return ExecuteDataset(CommandType.Text, cmdText, cmdParams);
    }
    //Connection String
    private static SqlConnection connection;
    //Attribute
    public static SqlConnection Connection
    {
        get
        {
            string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionStr"].ConnectionString;
            if (connection == null)
            {
                connection = new SqlConnection(connectionString);
                connection.Open();
            }
            else if (connection.State == System.Data.ConnectionState.Closed)
            {
                connection.Open();
            }
            else if (connection.State == System.Data.ConnectionState.Broken)
            {
                connection.Close();
                connection.Open();
            }
            return connection;
        }
    }
    public static SqlConnection GetConnection()
    {
        string connectionString = ConfigurationManager.ConnectionStrings["connectionStr"].ConnectionString;
        if (connection == null)
        {
            connection = new SqlConnection(connectionString);
            connection.Open();
        }
        else if (connection.State == System.Data.ConnectionState.Closed)
        {
            connection.Open();
        }
        else if (connection.State == System.Data.ConnectionState.Broken)
        {
            connection.Close();
            connection.Open();
        }
        return connection;
    }
    public static SqlParameter SetParameter(string name, object value)
    {
        return new SqlParameter(name, value);
    }
}
